In her 2012 book The Boy Kings, early Facebooker Kate Losse describes the tribulations of being a woman at a company that didn't get women. A new eBook by another early Facebook alum details just how uncomfortable it was.

The office really was a fraternity. Our original office was emblazoned with the Greek letters Tau Beta Phi, AKA "The Face Book," and was covered with graffiti. To make the experience all the more authentic, there was actually graffiti of a woman shitting in the women's bathroom. It had to be removed when a VC investor decided to visit the office.

There was a patio on the roof where we would drink beers, smoke and just talk about our future. For a while, unsurprisingly, people called the office "The Frat House." When the first women were hired at the office, the situation, as you can imagine, could no longer remain the same.

This jibes with a passage in Losse's book regarding office graffiti:

The graffiti in question is presumably the work of David Choe, the "street artist" whose pre-IPO mural netted
him hundreds of millions of dollars after Facebook went public. He also recently went on a podcast and talked
about having possibly raped a masseuse.